Method of folding by a jet of compressed air, applicable to a bending machine - unit and a device for the implementation of this process

摘要

944,357. Making cartons; folding edges on non-metallic sheet material. J. BOBST ET FILS S.A. Sept. 21, 1961 [Oct. 6, 1960; May 29, 1961], No. 33893/61. Headings B5D and B5K. In a folding gluing machine, flaps 10, 11, on blank 9 (Fig. 2) are bent up by air blasts from nozzles 12, 13, the blasts being controlled by an electromagnetic valve operated when the blank 9, travelling in the direction of the arrow 14, breaks light beams 17, 18 of photo-cells 15, 16 which are arranged to control said valve. In other modifications (not shown), metal feelers may replace the photo-cells or micro-switches may be used to detect the passage of a previously folded flap. All means of detecting the travelling blank are adjustable to allow for increasing speed of passage and different shapes of blank to be folded. In a modification, Fig. 5, the micro-switch 31 with detector arm 33 is held between rails 38, 39 and connected by a bar 40 to a piston 41 which in turn is acted upon by spring 43. As the speed of the machine is increased a band 46 drives a pump 45 faster and air travelling through a tube 44 forces the piston 41 back against the spring 43. The detector arm is thus moved in the opposite direction to that of the moving blanks, arrow 37, and so compensates for increasing speed. An adjustable air escape valve 47 is provided.